1. Field of the Invention
This invention relates to disk drive suspensions and, more particularly, to load beams for disk drive suspensions displaced by microactuators and having features allowing greater stroke sensitivity (or displacement response to microactuator elongation and contraction) for increased distance of stroke without loss of torsion performance with a given voltage input. The invention suspensions utilize microactuation by a piezoelectric crystal to shift the load beam distal end relative to the beam base portion over the disk to be read. The invention uses plural reverse deflections (or turns of direction) along the length of the suspension spring elements to provide a softer resistance to lateral movement and less constraint of the suspension movement that is responsive to longitudinal dimensional change in the piezoelectric crystals, while maintaining the structural integrity of the suspension. Manufacturing advantages accrue from the inventive use of the plural reverse deflections over the use of single deflections. Single deflections tend to spring back and plural, reverse deflections counteract this tendency. The invention enables effective microactuation of suspensions with the use of greatly reduced voltages, e.g. 5 volts, rather than 40 volts heretofore employed by virtue of heightened stroke sensitivity. Stroke sensitivity, measured in NMNOLT, is increased, for example, to over 41 NMNOLT from the just about 31 NMNOLT obtained with single deflection in the suspension spring elements.
2. Related Art
Load beams are used to carry sliders containing read/write heads adjacent spinning disks. The load beam has a base portion anchored to an actuator arm that pivotally shifts the load beam and its associated slider angularly to move between tracks on the disk. The mass and inertia of conventional actuators means it requires considerable power to operate them.